Carrot gun packs a punch; improves eyesight

Just in time for your garden’s carrot harvest [Lou] shows us how to make a carrot firing rifle. It’s cheap, easy, and quick. If you’ve got 15 buck and 15 minutes you can have one to call your own.

The loading method is quite easy. Shove a carrot in the muzzle as far as it will go, then cut of the excess. Finish up by using a ramrod to push the carrot stub the rest of the way into the barrel. Once you’ve gnawed down the rest of the carrot nub and connected a compressor hose to the rifle you’re ready to do some damage. The video after the break shows a carrot fired all the way through a cardboard box, and penetrating a gallon jug of water.

[Lou] uses CPVC for the project. It takes just a few lengths of pipe, pipe fittings, a valve, and a threaded metal compressor fitting. After gluing everything together he threads the compressor attachment in place and heads to the firing range.

Have a look at spudfiles.com if you want to see actually interesting build of air/gas powered veggie shooter.

That thing is very inefficient and dangerous. He should have use sprinkler/quick exhaust/diaphragm valve and copper/steel tubing insteed of a ball valve and PVC/CPCV piping (they make very sharp shard when they explode).

If I had to guess, it seems that the high pressure rating becomes irrelevant over time.I’m going to make a guess that the high/low pressure shock that happens when a line is unloaded/loaded or loaded/unloaded is what is causing the structure of pvc to deteriorate over time. if that’s a correct guess, then the conclusion would be that while it’s safe to use such a construction the first X number of times , at some point the structure of the pvc becomes sufficiently destabilized as to pose an explosion risk at a substantially lower pressure than what the pipe is rated for. Think of a water hammer effect, but with gas… the shock is more extreme at each moment, thus breaking down the pipe walls, or exploiting weak point(s). My mental calculations suggest that this pressure/failure overlap happens on a curve, and that running a pvc cannon at a pressure of, say, 30 or 40 psi would mean that you could use it much longer before a point of failure was reached, vs running it at a pressure of 100, 200, 0r 300 which would fail in an exponentially shorter period of uses. However, this presupposes that the actual length of pipe you’re using is without flaw.

Testing of such theories is best left to some sort of containment vessel. Given the known instability of pvc (and it’s derivatives), the clear conclusion is that there are better materials with which to make compression cannons than pvc, and that people who use pvc as their medium are taking substantial risk.

I’m just amazed he still has all his fingers after using that band saw! I also wonder how long that steel fitting is going to stay “threaded” into that pvc before it comes out close to the speed of one of those carrot ends…

I made this with Schedule 40 CPVC, which is rated at 480 psi and is routinely subjected to high water hammer pressures in your own house. 90 psi air, which has no water hammer effect, is hardly a match for CPVC. Also, the metal threads of the compressor fitting dig into the walls of the pipe, and is not going anywhere. I appreciate all the extra concern from some of you, but I designed this safely.

I have a Masters degree in Mechaical Engineering and a PhD in Hack. I do crazy stuff all the time, and I still have one eye and 6 fingers. I can take the pressure, and so can the gun.

Thanks for the concerns from some of you, but I designed this gun safely. There has been 60 psi coursing through the 480psi-rated CPVC in your own house house for years, and water-hammering to much higher pressures. A measly 90 psi non-water-hammered air compressor is no match for this gun.

I have a Masters in Mechanical Engineering and a PhD in Hack. I have done lots of crazy stuff and still have one eye and 6 fingers left. I can handle the pressure and so can the gun.

people like to spout of “safety” facts when pvc potato guns are built. You’d have been immune from this if you’d built it out of galvanized steel pipe and pressurized the canister with black powder (please don’t by the way, that was sarcasm).
We have too many so called experts on the dangers of using pvc.

While I am still not 100% convinced the PVC gun is dangerous, I built a metal one, this weekend, for those that are concerned. As an added bonus, it loads any size carrot and seems to be a bit more powerful.